Method of hydrogen generation through sodium borohydride hydrolysis using CaV2O6@CaSiO3@g-C3N4 nanocomposite

Abstract

A method of generating hydrogen includes contacting a graphite-phase carbon nitride, calcium metavanadate and calcium silicate (CaV2O6@CaSiO3@g-C3N4) nanocomposite with sodium borohydride (NaBH4) in water and hydrolyzing the sodium borohydride to generate hydrogen.

The invention claimed is: 
     
         1 . A method for hydrogen generation, comprising:
 contacting a graphite-phase carbon nitride calcium metavanadate and calcium silicate (CaV 2 O 6 @CaSiO 3 @g-C 3 N 4 ) nanocomposite with sodium borohydride in water; and   hydrolyzing the sodium borohydride to generate hydrogen.   
     
     
         2 . The method of  claim 1 , wherein the sodium borohydride is present in an amount of 0.5 to 1 grams (g) per 0.4 milligram (mg) of the CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite. 
     
     
         3 . The method of  claim 1 , wherein the CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite is present in an amount of 3.5 to 4.5 mg per 700 mg of the borohydride. 
     
     
         4 . The method of  claim 1 , wherein the contacting occurs at a temperature of 20 to 45 degrees Celsius (° C.). 
     
     
         5 . The method of  claim 1 , wherein the hydrogen is generated at a hydrogen generation rate of 2200 to 2400 milliliters per minute (mL/min) per gram of CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite at a temperature of 35° to 40° C. 
     
     
         6 . The method of  claim 1 , wherein the hydrolyzing generates at least 10 mL hydrogen within 2 minutes at a temperature of 35° to 40° C. 
     
     
         7 . The method of  claim 1 , wherein the hydrolyzing generates at least 30 mL hydrogen within 3 minutes at a temperature of 35° to 40° C. 
     
     
         8 . The method of  claim 1 , wherein the hydrolyzing generates at least 45 mL hydrogen within 5 minutes at a temperature of 35° to 40° C. 
     
     
         9 . The method of  claim 1 , wherein the hydrogen is generated at a hydrogen generation rate of 300 to 400 mL/min per gram of CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite at a temperature of 25° to 30° C. 
     
     
         10 . The method of  claim 1 , wherein the hydrolyzing generates at least 5 mL hydrogen within 2 minutes at a temperature of 25° to 30° C. 
     
     
         11 . The method of  claim 1 , wherein the hydrolyzing generates at least 21 mL hydrogen within 5 minutes at a temperature of 25° to 30° C. 
     
     
         12 . The method of  claim 1 , wherein the hydrolyzing generates at least 43 mL hydrogen within 10 minutes at a temperature of 25° to 30° C. 
     
     
         13 . The method of  claim 1 , wherein the hydrolyzing at a temperature of 35° to 40° C. has a hydrogen generation rate that is 8 to 11 times faster than the hydrolyzing without contacting with the CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite. 
     
     
         14 . The method of  claim 1 , wherein the hydrolyzing at a temperature of 25° to 30° C. has a hydrogen generation rate that is 4 to 6 times faster than the hydrolyzing without contacting with the CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite. 
     
     
         15 . The method of  claim 1 , wherein the CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite comprises a graphite-phase carbon nitride (g-C 3 N 4 ) in an amount of 20 to 40 percent by weight (wt. %), calcium silicate (CaSiO 3 ) in an amount of 20 to 40 wt. %, and calcium metavanadate (CaV 2 O 6 ) in an amount of 20 to 40 wt. %, based on a total weight of the CaV 2 O 6 /CaSiO 3 /g-C 3 N 4  nanocomposite. 
     
     
         16 . The method of  claim 1 , wherein the CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite is porous, and has an average pore diameter of 2 to 16 nanometers (nm). 
     
     
         17 . The method of  claim 1 , wherein the CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite is porous, and has a pore volume to 0.2 to 0.24 cubic centimeters per gram (cm 3 g −1 ). 
     
     
         18 . The method of  claim 1 , wherein the CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite comprises:
 a major CaV 2 O 6  phase;   a major CaSiO 3  phase; and   a minor g-C 3 N 4  phase,   wherein the CaV 2 O 6  phase and the CaSiO 3  phase are in a structure of nanowires, and   the g-C 3 N 4  phase is in a structure of nanosheets,   wherein the nanowires are dispersed in between the nanosheets.   
     
     
         19 . The method of  claim 1 , wherein the CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite has g-C 3 N 4  nanosheets with an interplanar spacing of 0.13 to 0.25 nanometers (nm). 
     
     
         20 . The method of  claim 1 , wherein the CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite is produced in a process, comprising:
 mixing a calcium salt and a metasilicate salt in a solvent to form a silicate product;   heating urea to form g-C 3 N 4  product;   heating ammonium metavanadate with xylose in nitric acid to form vanadate product;   microwaving the silicate product, the g-C 3 N 4  product, and the vanadate product in an organic solvent to form the CaV 2 O 6 @CaSiO 3 @g-C 3 N 4  nanocomposite.